In recent years, a progress in a thermal head is accompanied with utilization of a heat-sensitive recording material which has rapidly been expanding. In particular, in a prepaid card which has rapidly getting popular in the fields of communication, transportation and distribution, a magnetic information is shown on a card face as a visible information in many cases. Such the magnetic card is widely used as a high way card, a JR Orange card, an Io card, or a prepaid card in a department store and a super market.
However, an area in which the visible information can be expressed on such the magnetic card is limited, and in case of an expensive prepaid card, successive recording of the balances thereof leads to impossibility to display the information in some cases. In such the case, a new card is usually reissued to cope therewith, which raises a cost.
In order to solve such the problems, a reversible recording material in which recording and erasing can be carried out plural times on the same area is preferably used. Use of such the material makes it possible to erase an old information and display a new information and therefore, reissue of a new card due to impossibility of displaying the informations is not necessary.
There have so far been proposed as a heat sensitive recording material which can thus rerversibly record and erase the informations, those having a heat-sensitive recording layer in which an organic low molecular weight substance such as a higher alcohol or a higher fatty acid is dispersed in a resin matrix such as a polyvinyl chloride, a vinyl chloride-vinyl acetate copolymer, a polyester, and a polyamide JP-A-55-154198 (the term "JP-A" as used herein means an unexamined published Japanese patent application)!.
Formation and erasion of an image with such the material is carried out by utilizing a reversible change in a transparency in a heat-sensitive recording layer by a temperature. That is, this recording material shows a transparent state at some temperature (t.sub.1 to t.sub.1 ', provided that t.sub.1 &lt;t.sub.1 ') and shows an opaque state at a temperature higher than t.sub.1 '. A thermal head is preferred as a heating means for a recording layer particularly in the case that the recording layer is provided on the magnetic card. That is, a transparent state is set at an initial stage and then the portion is turned opaque by heating to a temperature higher than that (t.sub.1 ') of a thermal head to record a character and a pattern. Alternatively, an opaque state may be set at the initial stage and then the portion may be turned transparent by heating to a temperature (t.sub.1 to t.sub.1 ') with the thermal head for recording. In erasing these, it is heated to a temperature of (t.sub.1 to t.sub.1 ') in a former case and to a temperature higher than (t.sub.1 ') in a latter case with a heat roll or a thermal head.
Usually, a method in which a reversible recording material is coated directly on a card member is the most practical as a method for providing the reversible recording material on the card. For example, where it is desired to partially provide a recording area, it is easier to adhere them with an adhesive. Because of this, the present inventors tried to prepare a recording material having provided the reversible heat-sensitive recording material on one face of a substrate and an adhesive layer on the another face thereof. However, in recent years, such the recording material was used to provide a memory card and an IC card which are used for an electronic pocketbook with a function of a visible display, but even adhesion with a conventional adhesive as well as coating directly on a card generated an uneven color development and a blurred character due to large irregularities and undulations on the card, which prevented a tight contact to a thermal head.
The object of the present invention is to provide a reversible heat-sensitive recording material which can reversibly repeat to form and erase a record by heat and can readily be applied even to a substance having large irregularities and undulations, and various cards using this.